Friday, June 18, 2010

The 38-year-old fashion designer is to add to her brood with husband Alasdhair Willis later this year.

The couple already have two sons, Miller, five, and Beckett, two, and a three-year-old daughter, Bailey.

However, Miss McCartney admitted in February that she was keen to add to her family, saying: 'I'm kind of interested in having more children. Though right now I feel like I've only just stopped having them, so I'm ready to have a bit of a break first.'

The number four seems to run in the family. With the Beatles, her father, Sir Paul McCartney, was of course one of the Fab Four, while she herself was one of four children. She was seen this week with a big bag that covered her stomach as she arrived at her West London home fresh from the school run.

A source close to the designer told the Mail: 'Stella loves the idea of having a closeknit family, just like the one she grew up in. She's a great mum. She has been telling all her friends the good news.'

Pregnancy has become ever more "policed", with a litany of rules for parents-to-be on how to behave, a parenting conference is due to hear.

Researchers at the two-day seminar at Kent University will present fresh analysis of the decision to advise pregnant women to avoid any alcohol.

There have been mixed messages about drinking in pregnancy in recent years.

The impact of mounting efforts to involve fathers in the antenatal period will also be explored.

The Changing Parenting Culture conference next week is to explore the emergence of what it sees as new, often contradictory rules shaping pregnancy and pregnancy planning.

These include the role of stress in pregnancy, amid conflicting reports on the impact of the way a mother feels on the well-being of the growing fetus.

Some studies have suggested that stress in pregnancy can cause anything from physical abnormalities to behavioral problems.

Elizabeth Mitchell Armstrong, professor of sociology at Princeton University, will argue that maternal emotions are being "medicalized".

"To the list of pregnancy prescriptions and proscriptions comes another mandate: be happy, be calm. Pregnant women are exhorted to avoid stress and to moderate their emotions in order to produce a healthy baby.

"Yet the evidence behind this recommendation is exceedingly weak."

The conference will also look at the issue of Fetal Alcohol Syndrome (FAS) and accompanying disorders - the reason why pregnant women are advised to abstain from alcohol in many countries - including the UK, US, France and Australia.

The relationship between sustained heavy drinking in pregnancy and health problems such as growth and mental retardation is well-established - although alcoholic mothers will not necessarily have affected children - but evidence is lacking that low to moderate intake is harmful.

However concerns that some women may underestimate their drinking, as well as fears that a lack of evidence did not mean moderate consumption was safe, are thought to have informed the 2007 decision to advise pregnant women in England to abstain.

Dr Ellie Lee, a lecturer in social policy at the University of Kent, suggests that in "advocating abstinence without an evidence base, policy makers formalize a connection between uncertainty and danger".

She adds: "They have decided it is preferable that pregnant women take no risk even if there is no evidence of harm.

"But there are dangers associated with this approach, not least that such hyper risk-aversion sits uneasily with advice to parents against 'cotton wooling' or worrying too much about their children's health.

Fathers meanwhile are being increasingly encouraged to curb their drinking, stop smoking and eat well when a partner is pregnant, on the basis that his behavior is likely to influence hers.

Attendance at ante-natal sessions, as well as the birth, is now widely expected.

But research to be presented by Jonathan Ives and Heather Draper of the Centre for Biomedical Ethics at Birmingham University will question this mantra.

They suggest that involving men in the very medicalized aspects of their partner's pregnancy and labor - where their contribution is inevitably limited - is not necessarily the best preparation for all fathers.

"It's a good and positive step to promote male involvement, and we are not seeking to undermine that," says Dr Ives.

"But we are getting to a point where society has to ask if we are going about this the right way. It's time for debate."

New York City apartment buildings are often a menagerie of types, including old-timers who remember precisely who lived in each apartment 25 years ago, midlifers preoccupied with their families, and residents so new that they still find the clanging radiators and groaning midcentury elevators charming.

But one outgrowth of the real estate construction boom are buildings where everyone is new and moving in at similar stages of life. The residents are often young, but at one small building on Sackett Street in the Carroll Gardens neighborhood of Brooklyn, a large percentage of them are really young: Four of the six buyers had five babies among them when they went to contract in the fall and closed in April.

The sleep-deprived residents are settling into a rhythm that contrasts with the hushed order found in some buildings. The lobby often has an arsenal of Diapers.com boxes stacked at the entrance. Residents sometimes confuse cries emanating from other apartments as those of their own babies, and the first meeting of the condominium board was scheduled around feeding and sleep times. Besides the four pairs of new parents, a fifth buyer has a 4-year-old, a scooter-wielding preschooler named Quincy, the building’s oldest child.

Tucker Fort moved into a third-floor apartment in April with his wife, Megan, their nearly 3-year-old daughter, Phoebe, and their 6-month-old son, Roger. “It’s a nice perk because we’re all in the same situation,” he said. “In my old building I used to fret more when our baby was screaming in the middle of the night.”

Here, faint baby cries resonate from “upstairs, downstairs, all around you,” Mr. Fort said. Two newborns inhabit the two fourth-floor duplexes above the Forts, and newborn twins live on the floor below.

Residents have made the old joke that it could be the water, but the real answer is what’s in the floor plan. The building’s developer and architect, Alex Barrett, who has two children, designed the apartments with his own family in mind. All of the apartments have three bedrooms, and four of them have two full bathrooms.

His wife, Lindsay Barton Barrett, a Corcoran broker, said she cannot keep up with requests from families looking for three bedrooms in the neighborhood. (A recent search for three-bedroom apartments for sale in Carroll Gardens and Cobble Hill showed 15 available, ranging from $799,000 to $2.25 million.)

Still, Ms. Barrett, who sold the apartments in the Sackett Street building for $995,000 to $1.475 million, said that to have five babies in six apartments was “pretty extreme.”

Back at the Forts’ apartment, as Phoebe rode a black and orange bicycle around the kitchen island and Megan held Roger, the Forts spoke a little wistfully about their old home, a converted warehouse space in the West Village that suited them for 10 years, until Roger came along.

When Mr. Fort moved into the loft before marrying Megan, there were no babies in the building. By the time the couple had Phoebe, a network of doting older neighbors and a half-dozen families had formed. One neighbor used to make ribs that Phoebe savored, and another often offered to baby-sit. An 8-year-old girl passed along to Phoebe some of her outgrown clothes and Little Golden Books.

The Forts expect that after the children in their building reach a year old, the parents may have more time to socialize. Phoebe has already been riding her bike near Quincy and sizing him up as a prospective playmate.

Another owner, Sage Lehman, said that when she and her husband, Christopher Ronis, learned that two neighbors were also expecting, there was “definitely something nice about that.” She looks forward to her 7-month-old son Sam’s being able to run downstairs to their friends’ house.

The one couple without children does not seem to mind the baby talk. Jenny Capano and Joseph Purzycki were impressed by the child-focused thoughts of their neighbors at their recent board meeting, including their suggestion to place floor mats at the entrance so the children do not slip. They also said they could not believe how much more recycling the families generate.

Mr. Purzycki and Ms. Capano may still be wrapped up in working, traveling and having backyard parties. But they also try to shush their friends who come over when they get too loud.

“We are a bit more conscious if we are going to wake sleeping babies,” she said. “We don’t want to cross these boundaries, because we would like kids someday.”

Thursday, June 17, 2010

It looks like congratulations are in order for Sofia Coppola and her partner Thomas Mars!

The 39-year-old famed director was spotted going for a stroll with her newborn baby in SoHo, New York City on June 16. The last time we saw Sofia and Thomas, the Academy Award-nominee was still pregnant. Today, we see that Sofia has welcomed their second child! The couple have yet to make a baby announcement.

Citing high death rates among pregnant women during the recent H1N1 flu pandemic, researchers spelled out what they believe is an urgent need to perform clinical testing in that group, according an article in the New England Journal of Medicine.

The researchers called pregnant women "therapeutic orphans" because of their virtual exclusion from medical research.

"The importance of studying subpopulations that have previously been excluded from research is undeniable," wrote the authors. "Ironically, the effort to protect the fetus from research-related risks by excluding pregnant women from research places both women and their fetuses at great risk..."

It is both a tough argument and a paradox - and the recent H1N1 pandemic provides an interesting case study.

Pregnant women were hit hard during the pandemic. The virus was more likely to hospitalize and kill pregnant women compared with the general populace. The mantra from public health officials was for pregnant women to get vaccinated - that the potential benefits outweighed the risks - yet many mothers-to-be were worried about how the vaccine might affect the baby, and whether it could cause complications. The stark options were to get vaccinated and, with that, potentially risk the baby's health, or not get vaccinated and risk some impact from the H1N1 virus.

The same paradox exists regarding testing antidepressants on depressed pregnant women. Is it more important to address a mother's depression, which could lead to poor prenatal care - or worse, self-harm by the mother – and poor outcomes for the developing baby? Or is it more important to protect the fetus from possible risks surrounding antidepressants? They are vexing questions for sure.

In the NEJM article, authors attempt to address those questions by presenting ways to circumvent risks for testing pregnant women including, "...waiting to study pregnant women until adequate pre-clinical studies...have been completed...on non-pregnant women..." Or studying pregnant women who have already been prescribed a particular drug by their doctors, so that the only risk remaining would be taking a blood sample.

They say, "The complexity of studying the effects of medications in pregnant women should not stifle efforts to obtain scientifically rigorous data."

Studies have shown fathers who are active in their children's upbringing can significantly benefit their children's early development, academic achievement and well being. Now, a new study by University of South Florida researchers suggests that a father's involvement before his child is born may play an important role in preventing death during the first year of life - particularly if the infant is black.

The USF team sought to evaluate whether the absence of fathers during pregnancy contributes to racial and ethnic disparities in infant survival and health. Their findings were recently reported online in the Journal of Community Health.

"Our study suggests that lack of paternal involvement during pregnancy is an important and potentially modifiable risk factor for infant mortality," concluded the study's lead author Amina Alio, PhD, research assistant professor of community and family health at the USF College of Public Health. "A significant proportion of infant deaths could be prevented if fathers were to become more involved."

The researchers examined the records of all births in Florida from 1998 to 2005 – more than 1.39 million live births. Father involvement was defined by the presence of the father's name on the infant's birth certificate. While this measure does not assess the extent or quality of a father's involvement during pregnancy, other studies have established a link between paternal information on a birth record and prenatal paternal involvement.

Among the study's findings:

Infants with absent fathers were more likely to be born with lower birth weights, to be preterm and small for gestational age.

Regardless of race or ethnicity, the neonatal death rate of father-absent infants was nearly four times that of their counterparts with involved fathers.

The risk of poor birth outcomes was highest for infants born to black women whose babies' fathers were absent during their pregnancies. Even after adjusting for socioeconomic differences, these babies were seven times more likely to die in infancy than babies born to Hispanic and white women in the same situation.

Obstetric complications contributing to premature births, such as anemia, chronic high blood pressure, eclampsia and placental abruption, were more prevalent among women whose babies' fathers were absent during pregnancy.

Expectant mothers in the father-absent group tended to be younger, more educated, more likely to never have given birth, more likely to be black, and had a higher percentage of risk factors like smoking and inadequate prenatal care than mothers in the father-involved group.

Paternal support may decrease the mother's emotional stress, which has been linked to poor pregnancy outcomes, or promote healthy prenatal behavior, Dr. Alio suggested. For instance, some studies, including USF's, indicate that pregnant women with absent partners are more likely to report smoking during pregnancy and get inadequate prenatal care. Barriers to expectant fathers' involvement in the lives of their pregnant partners, including issues like unemployment, relationship status, and participation in prenatal visits, must be examined to increase the role of men during pregnancy, she said.

Improving the involvement of expectant fathers holds promise for reducing costly medical treatments for the complications of premature births as well as reducing infant mortality rates, particularly in black communities, Dr. Alio said. "When fathers are involved, children thrive in school and in their development. So, it should be no surprise that when fathers are present in the lives of pregnant mothers, babies fare much better."

Way back when, during the final decades of the last century, if a woman had a hard time conceiving, she saved her dollars by the tens of thousands and passed them over to a clinic specializing in assisted reproductive technology.

She might then shoot herself with stimulants and have her eggs retrieved, fertilized and implanted, hoping that science and the gods of modern fertility would conspire to impose their good will. This remains an exhausting method of achieving pregnancy, but the complexity is nothing compared to what takes place in “Google Baby,” a compelling documentary Wednesday on HBO2 that shows us how provincial the standard in-vitro fertilization procedure has become.

The film, produced and directed by the Tel Aviv filmmaker Zippi Brand Frank, examines the ways in which globalization has further complicated and diffused the fertility industry. “Google Baby,” though, is also the chronicle of an idea, one belonging to an Israeli entrepreneur named Doron, who gets into the business of using egg donors in the United States and gestational carriers in India to provide for the childless of the Western world.

Logistically, this involves freezing multiple donor embryos and shipping them to a surrogacy center in Anand, India, packaged in liquid nitrogen. Emotionally, it requires an enormous amount of fortitude on the part of childbearers in a culture where some regard surrogacy as a kind of prostitution.

What could easily be rendered as straight-out horrid exploitation is given an amazingly neutral hand as Ms. Brand Frank deftly avoids the clichés that typically materialize in any journalistic look at atypical reproduction. “Google Baby” — which derives its title from the practice of finding potential egg donors online — gives us no Upper East Side trophy wives choosing surrogacy to avoid the inconvenience of weight gain and relinquishing of gin and tonics. Nor does it show us Ivy League parents insisting on donors with perfect SAT scores and a proven record of Roger Federer-like displays of hand-eye coordination. (The demands of the affluent can seem insane in this universe, extending, as one reproductive endocrinologist once told me, even to shoe size.)

Doron himself was inspired to pursue this particular enterprise by his own experience becoming a parent as a gay man, and he seems moved to help other gay couples have children. The clinic in India is run by a doctor, Nayna Patel, who is insistent that her service not become a baby factory. She requires that clients either be childless or have no more than one child. Dr. Patel, who charges $6,000 for surrogacy, sees the service she provides as sisterly, “one woman helping another.” Offering a cost-benefit analysis to a surrogate, she explains that the prospective mother “cannot have a child which she longs for, which you are going to give, and you cannot have a house.”

“You cannot educate your son beyond school,” she continues. “For that they are going to pay.”

What parents pay for surrogacy outsourced to India is considerably less than the procedure can cost in the United States. Ms. Brand Frank’s camera moves fluidly to show us that the transaction is at once grossly unfair, given the risks to the childbearer, and yet at the same time its own kind of godsend because the money can and does make a difference to poorer women with otherwise limited opportunities. Among the uglier dimensions is the lack of appreciation men have when their wives are childbearers. What is far worse than an extreme capitalist is a bad husband.

Not long ago, Julia Fischer of the German Primate Center in Gottingen was amused to witness two of her distinguished male colleagues preening about a topic very different from the standard academic peacock points - papers published, grants secured, competitors made to look foolish.

"One of them said proudly, 'I have three children,' " Dr. Fischer recalled. "The other one replied, 'Well, I have four children.'

"Some men might talk about their Porsches," she added. "These men were boasting about their number of children." And while Dr. Fischer is reluctant to draw facile comparisons between humans and other primates, she couldn’t help thinking of her male Barbary macaques, for whom no display carries higher status, or is more likely to impress the other guys, than to strut around the neighborhood with an infant monkey in tow.

Reporting in the current issue of the journal Animal Behaviour, Dr. Fischer and her co-workers describe how male Barbary macaques use infants as “costly social tools” for the express purpose of bonding with other males and strengthening their social clout. Want to befriend the local potentate? Bring a baby. Need to reinforce an existing male-male alliance, or repair a frayed one? Don’t forget the baby.

It doesn’t matter if the infant is yours or not. Just so long as it has the downy black fur and wrinkly pinkish face that adult male macaques find impossible to resist. “They will hold up the infant like a holy thing, nuzzling it, chattering their teeth,” Dr. Fischer said. “It can be a bit bewildering to see.”

Just in time for Father’s Day come this and other recent studies that reveal surprising, off-road or vaguely unsettling cases of Males Behaving Dadly — attending to the young with an avidity and particularity long thought to be the province of the mother.

“Lots of primates are suckers for babies,” said Sarah Hrdy, the primatologist and author of “Mothers and Others” (Harvard University Press, 2009). Consider how the male of two small New World monkey species, the cotton-top tamarin and the common marmoset, reacts to a mate’s pregnancy.

His hormones change, the dendritic connections in his brain begin to change, and he puts on weight — all in preparation for the heavy lifting to come. Female marmosets and tamarins generally give birth to twins, which together weigh about 20 percent of what the father does, and from the moment the babies are born until they reach independence, the male will be expected to carry them most of the time. If he’s sitting, he’ll hold them on his lap. While he’s swinging through the trees, the twins will cling to the comforting thermal pads between his shoulder blades. If he hears the babies crying, he can’t help himself — he must fetch them and pick them up.

The researchers initially assumed that baby handling might have a tranquilizing effect on the males, but on measuring the macaques’ hormone levels, they found the opposite: carrying an infant caused a male’s stress hormones to spike. The scientists now propose that the males use the infants as “battle symbols,” as Dr. Fischer put it, “to show other males that they can bear the stress.”

Yes, fathers love to take charge, beat the odds, expand the nest. Reporting in the journal Science , David J. Varricchio of Montana State University and his colleagues offered evidence that for at least some species of birdlike carnivorous dinosaurs, fathers may have been the ones who cared for their young.

The researchers argued that to begin with, the repeated discovery of adult dinosaurs in close proximity to egg clutches indicated that dinosaurs didn’t just dump and dash, turtle style, but instead stuck around to protect the nest. What’s more, the total volume of each clutch was impressively large, suggesting input from more than one female.

Finally, the bones of the adults associated with the nests suggested that their owner might well have been male. A male that invited many females to mate with him and lay their heavy treasures in his nest. He was a good father. They had done their part. Now he would do the rest.

But all of these are unsuitable for daily wear in pregnancy because they do not provide the feet with the necessary support, according to Ms Jones.

As a rule, she says women should opt for 1.2in (3cm) heels as they shift weight a little further forward on to the feet, which can help alleviate discomfort.

If women must wear high heels, they should only do so very occasionally and at events where they will not be on their feet for too long, she adds.

"Many of the pregnant celebrities you see wearing high heels in magazines are attending events so, like them, try to keep your high-heeled, high-fashion shoes for a special occasion and stick to a more supportive shoe on a daily basis."

Have you noticed more interest from the insect community now that you're pregnant? There's a good chance that you are not imagining things. Pregnant women do get more mosquito bites! Around twice as many, according to one study. Why?

Mosquitoes use heat to see. So that furnace you've been feeling in bed at night is to blame. It's easier for a mosquito find you due to your higher body temperature. Pregnant women also exhale more carbon dioxide than other people, which is another way mosquitoes track down their victims.

So how do you avoid being bitten to bits?

Most people tend to reach for the bug spray. There’s no conclusive data saying there’s a risk from using the hard stuff (DEET) but for those of you who are skeeved out by the smell (or lack of conclusive data about its safety) there are lots of milder, safer alternatives. EWG.org has a list of the least toxic bug repellents. The list is not specifically for pregnant women, but there are many for babies. Citronella oil is considered a pretty safe option, and it can be used in candles instead of applied directly to the skin.

The problem is that some of these natural repellents don’t repel nearly as well as the nuclear DEET stuff. So you may end up cutting down on bug bites but not avoiding them entirely. Then there’s the physical block option: long sleeves, screens, or just staying inside at the buggiest times of day. Not always the most fun option in the moment, but it may be worth it to keep excruciating mosquito bites off your current list of middle of the night discomforts!

Although men may not be aware of it, they actually undergo hormonal changes as they prepare for fatherhood, says neuropsychiatrist Louann Brizendine, author of The Male Brain.

At first, those hormones tell them to panic, or at least pay attention.

Levels of a stress hormone called cortisol - the same ancient chemical that instructs men to fight or take flight - tend to spike about four to six weeks after men learn they're going to be fathers, subsiding as the mother's pregnancy progresses, Brizendine says

"It is a cortisol surge that wakes our brains up every morning," Brizendine says. "So this surge may put the father-to-be's brain on alert and in a sense wake him up to the impending reality of a new baby's coming, and alert him that he'd better get things ready."

Philip Andrew, who organizes a fathers' group in Lincoln, Neb., says he tried to channel his pre-baby anxiety into educating himself about infants. Concerned that he was unprepared to handle a baby, he and his wife signed up for childbirth and parenting classes at the hospital. Learning about what to expect helped ease his mind and allowed him to remain calm on the big day, Andrew says.

About three weeks before the baby arrives, levels of testosterone — sometimes called the "male hormone," associated with competitiveness, aggression and sex drive — fall by roughly a third, Brizendine says.

That may have helped the species to survive, she says. A human baby needs two full-time caregivers — maybe more. So a baby is more likely to survive if Dad is at home to help, rather than out looking for new romantic conquests, she says.

Bill Stratbucker, 40, was surprised at the things he did after his twins were born — such as going out to buy nipple shields for his wife, which help babies nurse. "Some part of me felt like I wanted to hold on to the way I was before kids," says Stratbucker, a pediatrician in Grand Rapids, Mich., whose twins are now 6 years old. "You just change and mature a lot."

Even the male brain changes, Brizendine says.

Tests show that men actually get better at hearing a baby's cry — zeroing in on the sound and responding to it — as the due date of their own child approaches.

Other hormonal changes are a head-scratcher, she says.

At the same time that testosterone is falling, a man's supply of prolactin — a hormone that helps mothers make milk — rises more than 20%, Brizendine says.

"We still don't know what prolactin is doing in dads," she says.

Male hormones begin to readjust when the baby is 6 weeks old, returning to pre-fatherhood levels by about the time the baby is walking, Brizendine says.

Scientists can't completely explain why men's hormones fluctuate, Brizendine says. It's possible that men are reacting to women's pheromones, airborne chemical messengers secreted by their skin and sweat glands, she says. Scientists think these chemicals may trigger a man's brain to "begin making the hormonal changes necessary for paternal behavior," she says.

These pheromones appear to work both ways, at least in animals. In a study of mice, the males released their own pheromones. That triggered the female mice to make more prolactin, which also stimulates the growth of maternal brain circuits, Brizendine says.

Through these unconscious chemical signals, she says, mothers and fathers may be spurring more loving, nurturing behavior in each other, increasing the odds their babies will survive.

It's possible, Brizendine says, that "the baby is actually in control from before birth in just this very way: The baby is controlling the hormones of the mother, and she is controlling the hormones of the father-to-be."

Babies exert long-term effects on their fathers. Studies show that dads who are more involved in child care have lower testosterone levels than uninvolved fathers. But do lower testosterone levels really make men more nurturing? Or does nurturing change a man's hormones? Scientists don't yet know.

Scientists have more solid answers when it comes to the ways that babies affect the brain.

Looking at a baby's face — with its pudgy cheeks and big eyes — causes the brain's "parental-instinct" area to light up within one-seventh of a second.

A baby's smile activates the same brain circuits involved with falling in love, Brizendine says.

As if practice makes perfect, Brizendine says, "the more a man holds and cares for his child, the more connections his brain makes for paternal behavior."

Parents say they need that fierce devotion to power through the tough times, waking every two hours to feed a hungry newborn or pacing the halls with a colicky 3-month-old.

By maintaining a little emotional distance — or a least a broader perspective — Andrew says fathers can help keep a household running. While moms focus on essentials such as breast-feeding, dads can keep the rest of the household from falling apart by doing housework, driving older kids to school or making sure that bills get paid.

"The dad has a bigger picture on things, instead of that laserlike focus on the baby," says Andrew, 39, whose children are 6, 8 and 13. "It works as a balance."

Monday, June 14, 2010

Indeed, occasional air travel is safe for healthy pregnant women, according to a new committee opinion issued by the American College of Obstetricians and Gynecologists.

That holds true even in the last month of pregnancy, although most doctors generally prefer that women stop air travel around 36 weeks in case they go into early labor, said Barth, chairman of ACOG's Committee on Obstetric Practice.

"Exercise normal precautions" by drinking lots of water, getting up and walking, wearing support stockings and keeping your seat belt fastened while seated, he advises soon-to-be moms who choose to fly. Because pregnant women are at increased risk of blood clots, these measures are "even more important," Barth said.

If your stomach has been on a roll during pregnancy, consider taking an anti-nausea pill before getting on a plane. Also, avoid consuming foods or drinks that can cause gas because gas will expand in your stomach at high altitudes.

Some airlines require a note from a doctor if a pregnant woman wants to travel up to a month before her due date. "It's not that flying is particularly dangerous at that time," Barth said. "It's that the probability of going into labor is higher," and airlines want to avoid that possibility.

If you have control over your schedule, traveling by plane in mid-pregnancy (14 to 28 weeks) is preferable because that's when the risks of miscarriage and premature labor are lowest, according to the Mayo Clinic.

The outlook is more restrictive for pregnant women with underlying medical issues such as heart disease or lung disease that could be exacerbated by air travel. They shouldn't fly at any point because of physiological changes — an increased heart rate, higher blood pressure and less oxygen in the blood — that take place at high altitude, the ACOG statement noted.

It updates a previous 2001 committee opinion with information from new studies that found air travel is generally safe for healthy pregnant women.

Also, air travel isn't recommended, even occasionally, for women who are at risk of premature labor or have other obstetric complications such as pregnancy-induced hypertension, Barth said.

He recollects a patient carrying twins who wanted to travel to London for an art show. In her 28th week of pregnancy, she thought she'd made plans far enough in advance to avoid any problems. But when the doctor examined her, her cervix was 2 centimeters dilated, a sign she might go into labor prematurely. The woman canceled her reservations and stayed home.

For pregnant women who travel constantly for work, flying can present a risk because of the exposure to cosmic radiation. This form of radiation comes from the sun and outer space and is more intense at higher altitudes. At one point it was thought the mother's body reduced a fetus's exposure to radiation; currently, this isn't believed to be the case, however.

Any passenger can calculate his or her exposure to cosmic radiation from a specific flight by visiting the Federal Aviation Administration's Web site http://tinyurl.com/cosmicrad.

Pregnant women who travel occasionally don't have to worry about radiation, even if they take long trips, the new ACOG statement said. Even the longest international flight will expose a passenger to no more than 15 percent of the recommended annual radiation limits.

Picking the time of day to give birth may not be a choice very many women can make, but it could influence her chances of a smooth delivery, new research shows.

In a study of more than 700,000 births at all Dutch hospitals between 2000 and 2006, researchers found that the risks of newborn death and admission to the neonatal intensive care unit were higher with nighttime than daytime deliveries.

The findings, say the researchers, are in line with trends in other studies not only in obstetrics, but in hospital intensive care units as well.

Overall, the new study found, infants at smaller community hospitals who were born in the evening (between 6 p.m. and midnight) or overnight into early morning (between midnight and 8 a.m.) were 32 percent to 47 percent more likely to die than those born during the day.

Larger medical centers that would see more high-risk pregnancies -- so-called tertiary centers - did not have as much of a difference between night and day. At these hospitals, only overnight births - as opposed to evening births -- were linked to an increased risk of newborn death.

The findings were similar when the researchers looked at the risk of all adverse birth outcomes together.

But they stress that, in developed countries, serious complications are rare no matter what time of day or night a woman delivers.

"It is very important indeed to realize that risks are generally low and that the level of care in these kinds of Western countries is high," senior researcher Dr. Eric A.P. Steegers, of Erasmus University Medical Center in Rotterdam, told Reuters Health in an e-mail.

Of the nearly 656,000 singleton births at community hospitals, between 0.05 and 0.09 percent of infants died during or soon after birth. Rates were higher among infants born at tertiary hospitals, but were still less than 1 percent.

It's possible, Steegers said, that the increased risks reflect the fact that fewer senior staff members -- including obstetricians, neonatologists and anesthesiologists -- are available during night shifts.

Supporting that idea, the researchers found fewer infant deaths and complications at community hospitals when senior staff were present. At night, when such staff are at home on call, less experienced doctors may be making the initial decisions on how to manage high-risk situations.

Steegers said that more research is needed, however, to understand the extent to which hospital organization plays into the higher risk of childbirth complications at night.

It's also possible that staff fatigue is a factor, since night-shift work is at odds with the body's natural rhythms. But unfortunately, naps don't seem to do the trick: It may take up to half an hour for sleepy minds to get back up to speed after a slumber, the researchers note.

Even if organizational factors at hospitals do explain the higher nighttime risks, Steegers said, it is not clear whether revamping the system would eliminate those risks.

For example, he noted, it might be possible to have senior staff available 24 hours a day if there were fewer hospitals providing obstetrics care. But fewer centers could well mean that some women would be delayed in getting to the hospital, which could increase the odds of complications.